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MAINTENANCE Orban Model 8400
Sample Rate Tolerance (PPM) Tolerance ( Hz)
32 kHz 50 PPM ±1.60 Hz
44.1 kHz 100 PPM ±4.41 Hz
48 kHz 50 PPM ±2.40 Hz
E)
Disconnect the digital source generator from the 8400.
8. Test the 8400’s stereo encoder.
A) Connect an accurate stereo monitor like the Belar FMMS-1 (“Wizard”) stereo de-
modulator to the 8400’s
COMPOSITE OUTPUT 1.
This is labeled
OUTPUT and appears on a BNC connector on the 8400’s rear
panel.
NOTE: The recommended Belar monitor is the only instrument we have
encountered that can accurately measure the performance of the 8400’s ste-
reo encoder. With most older-technology monitors, you will be measuring
the performance of the monitor, not the 8400’s encoder. (Of course, we have
not evaluated every monitor on the market.)
B)
Navigate to the 8400’s System Setup and choose Test Modes.
C)
Choose Tone. Set the test tone parameters as follows:
Frequency 400 Hz
Mod Level 91%
Mod Type L+R
Test: Pilot On
D) Navigate to Input/Output and then to screen Input/Output 3. Set the Output 1 Level
to make the stereo monitor read 100% total modulation.
E) Navigate to the 8400’s System Setup and choose Test Modes.
F)
Measure the L–R level on the stereo monitor at several frequencies, in units of dB
below 100% modulation. This is the main channel to subchannel crosstalk. It
should not exceed –70 dB, 50-15,000 Hz.
G) Set the Mod. Type to L–R. Measure the L+R level on the stereo monitor at several
frequencies, in units of dB below 100% modulation. This is the subchannel to main
channel crosstalk. It should not exceed –70 dB, 50-15,000 Hz.
H) Set the Mod. Type to LEFT. Measure the Right level on the stereo monitor at sev-
eral frequencies, in units of dB below 100% modulation. This is left into right ste-
reo separation. It should not exceed –70 dB, 50-15,000 Hz.
I) Set the Mod. Type to RIGHT. Measure the Left level on the stereo monitor at sev-
eral frequencies, in units of dB below 100% modulation. This is right into left ste-
reo separation. It should not exceed –70 dB, 50-15,000 Hz.
J) Set the Mod. Type to L–R and the Frequency to 5000.0 Hz. Measure the 38 kHz
subcarrier suppression on the stereo monitor. It should not exceed –65 dB.
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